code: def test_scalar_codec_decimal():
      codec = ScalarCodec(DecimalType(4, 3))
      field = UnischemaField(
          name="field_decimal",
          numpy_dtype=Decimal,
          shape=(),
          codec=codec,
          nullable=False,
      )
  
      value = Decimal("123.4567")
      assert codec.decode(field, codec.encode(field, value)) == value
  
file_path: petastorm/petastorm/tests/test_codec_scalar.py
imports: from decimal import Decimal
  import numpy
  import pytest
  from pyspark.sql.types import StringType, ByteType, ShortType, IntegerType, LongType, DecimalType, BooleanType, FloatType
  from petastorm.codecs import ScalarCodec
  from petastorm.unischema import UnischemaField
label_desc: Use image node_id 4 for calling a global function with example usage: test_scalar_codec_decimal() without return types